Leetcode - ZigZag Conversion Solution
The string "PAYPALISHIRING"
is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibility)
P A H N
A P L S I I G
Y I R
And then read line by line: "PAHNAPLSIIGYIR"
Write the code that will take a string and make this conversion given a number of rows:
string convert(string s, int numRows);
Example 1:
Input: s = "PAYPALISHIRING", numRows = 3
Output: "PAHNAPLSIIGYIR"
Example 2:
Input: s = "PAYPALISHIRING", numRows = 4
Output: "PINALSIGYAHRPI"
Explanation:
P I N
A L S I G
Y A H R
P I
Example 3:
Input: s = "A", numRows = 1
Output: "A"
Constraints:
1 <= s.length <= 1000
s
consists of English letters (lower-case and upper-case),','
and'.'
.1 <= numRows <= 1000
Solution in Python
class Solution:
def convert(self, s: str, numRows: int) -> str:
d = defaultdict(str)
r = 1
x = 1
for i in s:
d[x]+=i
x += r
if x == numRows or x==1:
r*=-1
return "".join(d.values())